Dornier Do 335

https://en.wikipedia.org/wiki/Dornier_Do_335

The Dornier Do 335 Pfeil ("Arrow") was a World War II heavy fighter built by the
Dornier company. The two-seater trainer version was called Ameisenbär
("anteater"). The Pfeil's performance was much better than other twin-engine
designs due to its unique push-pull configuration and the lower aerodynamic drag
of the in-line alignment of the two engines. It was Nazi Germany's fastest
piston-engined aircraft of World War II. The Luftwaffe was desperate to get the
design into operational use, but delays in engine deliveries meant that only a
handful were delivered before the war ended.

The origins of the Do 335 trace back to World War I when Claude Dornier designed
a number of flying boats featuring remotely driven propellers and later, due to
problems with the drive shafts, tandem engines. Tandem engines were used on most
of the multi-engine Dornier flying boats that followed, including the highly
successful Do J Wal and the gigantic Do X. The remote propeller drive, intended
to eliminate parasitic drag from the engine entirely, was tried in the
innovative but unsuccessful Do 14, and elongated, tubular drive shafts as later
used in the Do 335 saw use in the rear engines of the four-engined, twinned
tandem-layout Do 26 flying boat.

There are many advantages to this design over the more traditional system of
placing one engine on each wing, the most important being power from two engines
with the frontal area (and thus drag) of a single-engine design, allowing for
higher performance. It also keeps the weight of the twin powerplants near, or
on, the aircraft centerline, increasing the roll rate compared to a traditional
twin. In addition, a single engine failure does not lead to asymmetric thrust,
and in normal flight there is no net torque, so the plane is easy to handle. The
four-surface set of cruciform tail surfaces in the Do 335's rear fuselage design
included a ventral vertical fin–rudder assembly to project downwards from the
extreme rear of the fuselage, in order to protect the rear propeller from an
accidental ground strike on takeoff. The presence of the rear pusher propeller
also mandated the provision for an ejection seat for safe escape from a damaged
aircraft, and designing the rear propeller and dorsal fin mounts to use
explosive bolts to jettison them before an ejection was attempted – as well as
twin canopy jettison levers, one per side located to either side of the forward
cockpit interior just below the sills of the five-panel windscreen's sides, to
jettison the canopy from atop the cockpit before ejection.

On 23 May 1944, Hitler, as part of the developing Jägernotprogramm (Emergency
Fighter Program) directive, which took effect on 3 July, ordered maximum
priority to be given to Do 335 production. The main production line was intended
to be at Manzell, but a bombing raid in March destroyed the tooling and forced
Dornier to set up a new line at Oberpfaffenhofen. The decision was made, along
with the rapid shut-down of many other military aircraft development programs,
to cancel the Heinkel He 219 night fighter, which also used the DB 603 engines
(in well-unitized installations), and use its production facilities for the Do
335 as well. However, Ernst Heinkel managed to delay, and eventually ignore, its
implementation, continuing to produce examples of the He 219A.

At least 16 prototype Do 335s were known to have flown (V1–V12, W.Nr
230001-230012 and Muster-series prototypes M13–M17, W.Nr 230013-230017) on a
number of DB603 engine subtypes including the DB 603A, A-2, G-0, E and E-1. The
first preproduction Do 335 (A-0s) starting with W.Nr 240101, Stammkennzeichen
VG+PG, were delivered in July 1944. Approximately 22 preproduction aircraft were
thought to have been completed and flown before the end of the war, including
approximately 11 A-0s converted to A-11s for training purposes. One such
aircraft was transferred to the Royal Aircraft Establishment in Farnborough, and
later, after a rear-engine fire burnt through the elevator controls during a
flight, crashed onto a local school.


Role
Fighter-bomber

Manufacturer
Dornier Flugzeugwerke

First flight
26 October 1943

Introduction
1944

Retired
1945

Status
Retired

Primary user
Luftwaffe

Produced
1944–1945

Number built
37

Flight tests

The first 10 Do 335 A-0s were delivered for testing in May. By late 1944, the Do
335 A-1 was on the production line. It was similar to the A-0 but with the
uprated DB 603E-1 engines of some 1,324 kW (1,800 PS) take-off power rating
apiece on 87 octane "B4" lignite-derived synthetic fuel, and two underwing
hardpoints for additional bombs, drop tanks or guns. It had a maximum speed of
763 km/h (474 mph) at 6 500 m (21 300 ft) with MW 50 boost, or 686 km/h (426
mph) without boost, and climbed to 8 000 m (26 250 ft) in under 15 minutes. Even
with one engine out, it reached about 563 km/h (350 mph).

Delivery commenced in January 1945. When the United States Army overran the
Oberpfaffenhofen factory in late April 1945, only 11 Do 335 A-1 single-seat
fighter-bombers and two Do 335 A-12 trainers had been completed.

French ace Pierre Clostermann claimed the first Allied combat encounter with a
Pfeil in April 1945. He describes leading a flight of four Hawker Tempests from
No. 3 Squadron RAF over northern Germany, when he intercepted a lone Do 335
flying at maximum speed at treetop level. Detecting the British aircraft, the
German pilot reversed course to evade. Despite the Tempests' considerable low
altitude speed, the Royal Air Force fighters were not able to catch up or even
get into firing position.

Specifications (Do 335 A-1)

General characteristics
Crew: 1
Length: 13.85 m (45 ft 5 in)
Wingspan: 13.8 m (45 ft 3 in)
Height: 5 m (16 ft 5 in)
Wing area: 38.5 m2 (414 sq ft)
Airfoil: root: NACA 23018-630; tip: NACA 23012-635
Empty weight: 7,260 kg (16,006 lb)
Gross weight: 9,600 kg (21,164 lb)

A-6 10,085 kg (22,234 lb)Fuel capacity: 1,230 l (320 US gal; 270 imp gal) main
fuel tank (single-seat) with various extra tankage in the weapons bay and wings,
depending on variant
Powerplant: 2 × Daimler-Benz DB 603E-1 V-12 inverted liquid-cooled piston
engines for take-off
1,417 kW (1,900 hp) at 1,800 m (5,900 ft)Propellers: 3-bladed VDM, 3.5 m (11 ft
6 in) diameter constant-speed tractor and pusher propellers

Performance
Maximum speed: 763 km (474 mph, 412 kn) at 6,500 m (21,300 ft)
A-6 690 km/h (430 mph; 370 kn) at 5,300 m (17,400 ft)Cruise speed: 685 km (426
mph, 370 kn) at 7,200 m (23,600 ft)
Economical cruise speed: 452 km/h (281 mph; 244 kn) at 6,000 m (20,000 ft)
Range: 1,395 km (867 mi, 753 nmi) on full internal fuel at max. continuous power
2,060 km (1,280 mi; 1,110 nmi) at economical cruise powerService ceiling: 11,400
m (37,400 ft)
Time to altitude: 1,000 m (3,300 ft) in 55 seconds ; 8,000 m (26,000 ft) in 14
minutes 30 seconds

Armament

Guns: 1 × engine mounted 30 mm (1.18 in) MK 103 cannon with 70 rpg plus 2 × 20
mm (0.79 in) MG 151/20 cowl-mount, synchronized autocannon with 200 rpg
Bombs: Up to 1,000 kg (2,200 lb) bombload in internal weapons bay and two
underwing pylons




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